This invention relates to a feed regulator means for the work feeding mechanism of a sewing machine, in particular, of the drop feed type wherein the work engaging feed dog is elevated into work engagement during the feed advance stroke, and dropped out of work engagement during the return stroke. U.S. Pat. No. 3,527,183, issued Sept. 8, 1970, discloses a drop feed mechanism of this type. A significant problem in connection with this type of feed mechanism is the difficulty of providing manual control of the amplitude of stitch length of a pattern that is being sewn under pattern cam control and with the same mechanism, control the stitch length and with the pattern cam disengaged. Ideally, there should be a quick reverse capability that will operate independently of and override the operation of the pattern cam. It is considered desirable to provide a single integrated control that will easily and accurately perform these functions. U.S. Pat. No. 3,834,334, issued Sept. 10, 1974, discloses such a unitary control. It includes a feed regulator shaft rotatably mounted in the frame of the sewing machine, operably connected to a feed dog and adapted to influence movement imparted thereto, and a feed regulator lever arm secured to the regulator shaft. A floating link member is carried at one end thereof by an element associated with the pattern cam feed linkage system and is provided at its other end with a pin positionable along said feed regulator lever arm and engagable therewith. Manually operable means are provided for guiding said pin along the feed regulator lever arm for a stitch length selection and for simultaneously establishing the proportionate amount of motion transmitted from the pattern cam to the regulator shaft. Additionally, a manually actuated quick reverse feature is disclosed which overrides the manual or pattern cam controlled feed modes.
The above citations comprise what the applicant believes to be the closest prior art of which he is aware that is relevent to the examination of this application.